CstF-64 and 3'-UTR cis-element determine Star-PAP specificity for target mRNA selection by excluding PAPα

• Published in: Nucleic acids research 2016-01, Vol.44 (2), p.811-823
• Main Authors: Kandala, Divya T, Mohan, Nimmy, A, Vivekanand, A P, Sudheesh, G, Reshmi, Laishram, Rakesh S
• Format: Article
• Language: English
• Subjects: 3' Untranslated Regions; Apoptosis Regulatory Proteins - genetics; Binding Sites; Cell Line; Cleavage Stimulation Factor; Humans; Membrane Proteins - genetics; Mitochondrial Proteins; Mutation; NAD(P)H Dehydrogenase (Quinone) - genetics; Nucleotide Motifs; Nucleotidyltransferases; Poly A; Polynucleotide Adenylyltransferase - genetics; Polynucleotide Adenylyltransferase - metabolism; Regulatory Sequences, Nucleic Acid; RNA; RNA Precursors - metabolism; RNA, Messenger - genetics; RNA, Messenger - metabolism; RNA-Binding Proteins - genetics; RNA-Binding Proteins - metabolism; Substrate Specificity
• ISSN: 0305-1048; 1362-4962
• DOI: 10.1093/nar/gkv1074

Almost all eukaryotic mRNAs have a poly (A) tail at the 3'-end. Canonical PAPs (PAPα/γ) polyadenylate nuclear pre-mRNAs. The recent identification of the non-canonical Star-PAP revealed specificity of nuclear PAPs for pre-mRNAs, yet the mechanism how Star-PAP selects mRNA targets is still elusive. Moreover, how Star-PAP target mRNAs having canonical AAUAAA signal are not regulated by PAPα is unclear. We investigate specificity mechanisms of Star-PAP that selects pre-mRNA targets for polyadenylation. Star-PAP assembles distinct 3'-end processing complex and controls pre-mRNAs independent of PAPα. We identified a Star-PAP recognition nucleotide motif and showed that suboptimal DSE on Star-PAP target pre-mRNA 3'-UTRs inhibit CstF-64 binding, thus preventing PAPα recruitment onto it. Altering 3'-UTR cis-elements on a Star-PAP target pre-mRNA can switch the regulatory PAP from Star-PAP to PAPα. Our results suggest a mechanism of poly (A) site selection that has potential implication on the regulation of alternative polyadenylation.